PMP 400/430 and PTP 200/230 Series Configuration and User Guide
pmp-0042 (March 2014)
Page 72 of 98
64 QAM
SISO -73
dBm
-
64 QAM
MIMO -
-70
dBm
256 QAM
MIMO -
-60
dBm
When the PMP 430 AP is replaced by the PMP 450 AP, the uplink sensitivity values for each modulation are
now higher, meaning that the PMP 430 SM may now support a lower modulation mode in the uplink
transmission. Since the PMP 430 SM can only transmit in SISO mode, the MIMO reception capability of the
PMP 450 AP is not utilized.
If the PMP 430 SM is replaced by a PMP 450 SM, the downlink sensitivity values are also higher now, again
possibly resulting in a lower modulation mode being used in the downlink. However, the PMP 450 AP – PMP
450 SM pair can now transmit and receive using MIMO modulation, therefore doubling the throughput for
each modulation mode.
Because of the different sensitivity values between a PMP 430 system and a PMP 450 system, some PMP
430 SMs may need antenna augmentation in order to connect to the PMP 450 AP. More details are given in
the Link Budget comparison section below.
Throughput
The peak throughput of a PMP 430 sector using a 20 MHz channel is around 45 Mbps.
The peak throughput of a PMP 450 sector using a 20 MHz channel is around 128 Mbps.
The peak throughput of a sector having a PMP 450 AP and PMP 430 SMs using a 20 MHz channel is
around 48 Mbps.
The difference is given by the fact that the PMP 450 system can communicate in MIMO mode, which
doubles the throughput for each modulation mode, and also by the fact that PMP 450 can communicate in
256 QAM mode, which provides a 33% increase in throughput compared to the 64 QAM mode.
The 1/16 CP in the two systems corresponds to two different CP lengths in µs. A PMP 450 system with CP
equal to 1/16 has the same CP time in µs as a PMP 430 system with CP equal to 1/8.
The throughput of a link between a PMP 450 AP and a PMP 430 SM is equal to half the throughput of a link
between a PMP 450 AP and a PMP 450 SM at the same distance because the PMP 430 SM can only
communicate in SISO mode, while the PMP 450 SM can communicate in MIMO mode. The exception is for
SMs very close to the AP, because the PMP 450 SMs can support 256 QAM mode, while the PMP 430 SMs
cannot.
The throughput of a link between a PMP 450 AP and a PMP 430 SM is also approximately equal to the
throughput of a link between a PMP 430 AP and a PMP 430 SM.
The peak throughput of a PMP 450 AP connected to both PMP 430 SMs and PMP 450 SMs depends on the
ratio of the PMP 430 SMs and PMP 450 SMs. If most of the SMs connected to the PMP 450 AP are PMP
430 SMs, then the PMP 450 AP throughput will be closer to 48 Mbps; if most of the SMs connected to the
PMP 450 AP are PMP 450 SMs, then the PMP 450 AP throughput will be closer to 128 Mbps.